/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.classfile.util;

import proguard.classfile.*;
import proguard.classfile.visitor.*;

/**
 * This MemberVisitor lets a given parameter visitor visit all the parameters of the methods that it visits. The
 * parameters optionally includes the 'this' parameter of non-static methods, but never the return value.
 *
 * @author Eric Lafortune
 */
public class AllParameterVisitor implements MemberVisitor {
    private final boolean includeThisParameter;
    private final ParameterVisitor parameterVisitor;

    /**
     * Creates a new AllParameterVisitor for the given parameter visitor.
     */
    public AllParameterVisitor(boolean includeThisParameter, ParameterVisitor parameterVisitor) {
        this.includeThisParameter = includeThisParameter;
        this.parameterVisitor = parameterVisitor;
    }

    // Implementations for MemberVisitor.

    public void visitProgramField(ProgramClass programClass, ProgramField programField) {
        visitFieldType(programClass, programField, programField.referencedClass);
    }

    public void visitLibraryField(LibraryClass libraryClass, LibraryField libraryField) {
        visitFieldType(libraryClass, libraryField, libraryField.referencedClass);
    }

    public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod) {
        visitParameters(programClass, programMethod, programMethod.referencedClasses);
    }

    public void visitLibraryMethod(LibraryClass libraryClass, LibraryMethod libraryMethod) {
        visitParameters(libraryClass, libraryMethod, libraryMethod.referencedClasses);
    }

    // Small utility methods.

    /**
     * Lets the parameter visitor visit the type of the given field.
     */
    private void visitFieldType(Clazz clazz, Field field, Clazz referencedClass) {
        String descriptor = field.getDescriptor(clazz);
        parameterVisitor.visitParameter(clazz, field, 0, 1, 0, ClassUtil.internalTypeSize(descriptor), descriptor,
            referencedClass);
    }

    /**
     * Lets the parameter visitor visit the parameters of the given method.
     */
    private void visitParameters(Clazz clazz, Method method, Clazz[] referencedClasses) {
        String descriptor = method.getDescriptor(clazz);

        // Count the number of parameters and their total size.
        int parameterCount = 0;
        int parameterSize = 0;

        int index = 1;

        loop:
        while (true) {
            char c = descriptor.charAt(index++);
            switch (c) {
                case ClassConstants.TYPE_LONG:
                case ClassConstants.TYPE_DOUBLE: {
                    // Long and double primitive types.
                    parameterSize++;
                    break;
                }
                default: {
                    // All other primitive types.
                    break;
                }
                case ClassConstants.TYPE_CLASS_START: {
                    // Class types.
                    // Skip the class name.
                    index = descriptor.indexOf(ClassConstants.TYPE_CLASS_END, index) + 1;
                    break;
                }
                case ClassConstants.TYPE_ARRAY: {
                    // Array types.
                    // Skip all array characters.
                    while ((c = descriptor.charAt(index++)) == ClassConstants.TYPE_ARRAY) {
                    }

                    if (c == ClassConstants.TYPE_CLASS_START) {
                        // Skip the class type.
                        index = descriptor.indexOf(ClassConstants.TYPE_CLASS_END, index) + 1;
                    }
                    break;
                }
                case ClassConstants.METHOD_ARGUMENTS_CLOSE: {
                    break loop;
                }
            }

            parameterCount++;
            parameterSize++;
        }

        // Visit the parameters.
        int parameterIndex = 0;
        int parameterOffset = 0;
        int referenceClassIndex = 0;

        // Visit the 'this' parameter if applicable.
        if (includeThisParameter && (method.getAccessFlags() & ClassConstants.ACC_STATIC) == 0) {
            parameterVisitor.visitParameter(clazz, method, parameterIndex++, ++parameterCount, parameterOffset++,
                ++parameterSize, ClassUtil.internalTypeFromClassName(clazz.getName()), clazz);
        }

        index = 1;

        while (true) {
            int newIndex = index + 1;
            int thisParameterSize = 1;
            Clazz referencedClass = null;

            char c = descriptor.charAt(index);
            switch (c) {
                case ClassConstants.TYPE_LONG:
                case ClassConstants.TYPE_DOUBLE: {
                    // Long and double primitive types.
                    thisParameterSize = 2;
                    break;
                }
                default: {
                    // All other primitive types.
                    break;
                }
                case ClassConstants.TYPE_CLASS_START: {
                    // Class types.
                    // Skip the class name.
                    newIndex = descriptor.indexOf(ClassConstants.TYPE_CLASS_END, newIndex) + 1;
                    referencedClass = referencedClasses == null ? null : referencedClasses[referenceClassIndex++];
                    break;
                }
                case ClassConstants.TYPE_ARRAY: {
                    // Array types.
                    // Skip all array characters.
                    while ((c = descriptor.charAt(newIndex++)) == ClassConstants.TYPE_ARRAY) {
                    }

                    if (c == ClassConstants.TYPE_CLASS_START) {
                        // Skip the class type.
                        newIndex = descriptor.indexOf(ClassConstants.TYPE_CLASS_END, newIndex) + 1;
                        referencedClass = referencedClasses == null ? null : referencedClasses[referenceClassIndex++];
                    }
                    break;
                }
                case ClassConstants.METHOD_ARGUMENTS_CLOSE: {
                    // End of the method parameters.
                    return;
                }
            }

            parameterVisitor.visitParameter(clazz, method, parameterIndex++, parameterCount, parameterOffset,
                parameterSize, descriptor.substring(index, newIndex), referencedClass);

            // Continue with the next parameter.
            index = newIndex;
            parameterOffset += thisParameterSize;
        }
    }
}
